DESCRIPTION: In both humans and animals prenatal exposure to ethanol increases susceptibility to subsequent ethanol abuse and alters related aspects of responsiveness to ethanol. Postnatal exposure to ethanol also has been found to increase later ethanol intake and related aspects of responsiveness to ethanol in animals. Early onset of ethanol use in adolescence or even pre-adolescence has been shown to be associated with a greater probability of ethanol abuse in adulthood, although causality in these studies with humans has yet to be demonstrated. One determinant of ingestion and related responsiveness to ethanol during early adolescence may be still earlier exposure to ethanol, a possibility to be explored in the present experiments. Toward improvement over previous experimental procedures in which early ethanol exposure occurs in relatively stressful circumstances, we propose to provide early exposure to ethanol in relatively nonstressful, ecologically representative circumstances and assess the consequences for responsiveness to ethanol in adolescence. Our preliminary results indicate that as adolescents, the offspring of dams living with their litter in large enclosures and free to consume ethanol ad libitum chose to drink relatively large amounts of ethanol. The present proposal is to determine the ontogenetic locus of this effect -- whether exposure during gestation, lactation or weaning is differentially effective -- and to determine controlling parameters of this effect. The second proposed step is to assess the breadth of consequences from these forms of early exposure for several key indices of responsiveness to ethanol during adolescence.